You have 2 apples, get 3 more, and then lose 2 of them.
So, you HAVE 2 apples, and if you get 3 more, you can add it to the 2.
In total at the moment, you have 5 apples. Now, you lose 2 more. We can subtract that from our total number of apples.
We now know that you are left with
3 apples.